2*2 MOBPEOLOGY AND EVOLUTION
head .3! the fibula. The filial!* anticus is large. The fiolw arises from the fibula alone, as in the higher Apes: and the tiliali*posticu* has its origin restricted to the fibula as well.
Theplanfari*, contrary to the condition in the higher Apes, is large and its tendon ends in the plantar fascia. The latter sends slips to the digits, that to the hallux being strong; and the same condition is met with in the Chimpanzee.
The flexor Irevi* digiforum, sends tendons to the four outer digits, but this is not always the case in the higher Apes. The tendons are perforated, as in the case of the flexor snbliruis muscle, by tendons of the deep flexor muscles. The fltxor longns tligitorum and -flexor longus hnllttci* send tendons to each of the five toes; so it is evident that the hallux receives two flexors, but the other digits each receive three. In the higher Apes the conditions are simpler.
The Alimentary Canal.—The tongue has a large sublingual plate, whose apex is divided into several denticles, which fit in between the lower incisor teeth ; and it has been suggested that these act as natural toothbrushes. In Chiromyx there is an apical hook, which keeps the space between the two rodent-like lower incisor teeth clear. In the higher Primates, the sublingua,; which is a vestigial structure, is absent, or reduced to the state of plicse firnbriatae. The palate has well-marked transverse rugae. The stomach is simple, the duodenum is large and the long caecum has a tapering vermiform appendix. The colon has a pendent colic loop.
The pancreas is narrow, but is otherwise not peculiar.